The invention relates to an arrangement for filtering hydraulic fluid at least one filter element in a hydraulic circuit, having a feed channel which leads the unfiltered hydraulic fluid to the filter element, having a discharge channel which leads away the filtered hydraulic fluid out of the filter element, having a bypass line which connects the feed channel to the discharge channel, with the filter element being bypassed in the process, having a pressure switching valve which is arranged in the bypass line and, in the case of a certain change in pressure caused by the contamination of the filter, opens the bypass line, and having a means for indicating the state of contamination of the filter element, this arrangement being in accordance with the preamble of claim 1.
Such an arrangement belongs to the prior art and is known, for example, from various ranges of axial piston pumps which are available on the market from the applicant. In this case, the filter element is configured, for example, as a full-flow filter with an upstream filling pump and is often combined with the axial piston pump. Bypassing the contaminated filter element by a bypass line has the advantage that, although contaminated hydraulic fluid is delivered, malfunctioning of the axial piston machine is avoided. It is nevertheless necessary to obtain information regarding the degree of contamination of the filter element. The means for indicating the state of contamination of the filter element is used for this purpose. The pressure switching valve in the bypass line and the indicating means are separate devices, in the case of the prior art, which both operate reliably and thus have to be configured and installed with a certain amount of care.
The object of the invention is to provide an arrangement of the type mentioned in the introduction which is of simplified design, operates reliably and provides for further information-giving and control possibilities.